Salt River and Wyoming Ranges

Problèmes avalancheux

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Unlikely

  Taille

  1–2

  Wind slabs with depths up to 2 feet are still lingering in steep, wind loaded terrain at the upper elevations. These slabs have become less sensitive to human triggers over the past few days, however, triggering one of these slabs may still be possible on very steep slopes. Obvious signs of instability such as cracking or collapsing may not be present as you approach a wind loaded slope. Watch for stiff wind affected snow that may feel “punchy” if you probe or dig. 

  Cornice Falls: Cornices have grown large and failures are possible. Give cornices a wide margin and be careful along ridgelines as they can break further back than expected. Limit exposure under cornices, particularly in the afternoon. Cornice falls are the most likely way to trigger a very large persistent slab avalanche. Check out this observation highlighting recent Cornice Falls.

  

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Possible

  Taille

  2–3

  Weak snow that formed in December persists at the base of the snowpack across the entire Greys River forecast zone. However, the thickness of the hard slabs that overlay this weak snow varies based on geographic location. In the middle and upper elevations of the Salt, Snake River, and deeper portions of the Wyoming Range, these weak layers are buried 3-5+ feet deep making it difficult for a human to impact them. Despite being less reactive to humans, large triggers such as cornice falls have been able to produce very large avalanches in locations where the snowpack is deep. In shallow parts of the forecast zone, such as the far eastern side of the Wyoming Range, these slabs are only 2-3 feet thick making it possible for humans to trigger avalanches on the buried weak layers. 

  Careful snowpack evaluation is required in this zone due to variable snow depths. Probing or digging can provide useful information about the depth to the weak layers preserved at the bottom of the snowpack. This evaluation is critical if you are riding in a shallow part of the zone. Total snow depth less than 6 feet (200cm) is a red flag. Very steep, hanging snowfields above cliffs and rocky wind affected slopes should be considered suspect in all parts of the zone. Keep in mind that a large windslab release orcornice fall could trigger one of these very large avalanches. Limiting your overhead exposure to these hazards is a smart move.